1. Field of the Invention
The present invention relates to a self-lubricating transmission device in which a pinion has a plurality of pin rollers, some of which engage with a rectilinear rack, particularly concerns to a self-lubricating transmission device which is improved to automatically supply the lubrication oil to the pinion when actuated to rotate the pinion along the rack.
2. Description of Related Art
A rack combined with a pinion has been known as a rack-and-pinion type steering device or a rack-and-gear device as disclosed by Japanese Laid-open Patent Application Nos. 08-34354 and 2000-65176 (each referred to as first and second reference hereinafter).
The first reference teaches that a helical spring is used as an urging means to absorb a displacement of the rack through a rotational movement of a rack guide means when a distance between the rack and the pinion fluctuates so as to reduce a frictional quantity of the rack guide means during the operation.
The second reference teaches that an elastic member is provided at a position lower than an addendum flank of the gear is placed. When the device is actuated, the gear is brought into engagement with the rack through an urging force of an intermediary elastic member so as to mitigate an induced level of noise and vibration.
Japanese Laid-open Patent Application No. 10-184842 (referred to as third reference hereinafter) teaches that racks are applied to a pinion device which requires a lengthened stroke upon transferring a factory robot, a component part stocker or a washing line.
In recent years, it may be necessary in big electronic factories to transfer bundles of ultra-thin vitreous sheets for an extended distance along the rectilinear rack so that the thin vitreous sheets are applied to liquid-crystal displays in an assembly location. In this instance, it is quintessential to lubricate the pinion in order to maintain a smooth engagement with the rack so as to provide the pinion with a swift and low-noise rotational movement.
In order to lubricate the pinion as an oil-supplying work, it requires a user to employ a spatula so as to manually take some lumps of grease out of a solid oil container.
This makes the oil-supplying work often and rendering the oil-supplying work time-consuming and costly. It is often the case with the oil-supplying work to wastefully supply a larger amount of the grease to the pinion for the fear that the grease will run out while actuating the pinion.
Especially upon employing the extended racks, it becomes necessary to manually supply the grease to the pinion along the extended racks to make the oil-supplying work laborious.
Therefore, the present invention has been made with the above drawbacks in mind, it is a main object of the invention to provide a self-lubricating transmission device which is capable of automatically lubricating the pinion evenly at the right time for an appropriate amount of a lubrication oil, this obviating the lubrication oil being wastefully used, while at the same time, making a lubrication work quick, labor-saving and user-friendly.